You are here

Food

Pasteurization is one of the more mild forms of thermal processing that kills pathogens in milk and increases its safety and shelf life. Modern pasteurization uses high temperature and short time to kill pathogens in the milk. It kills off the most heat-sensitive pathogens while retaining the qualities of milk that consumers expect. This amounts to heating the milk to 161° F (72° C) for 15 seconds by running the milk through a tube of which the size and diameter takes the milk exactly 15 seconds to pass.

It is a device that uses the evaporation to cool a space that can be used to store food or water. An illustration of one version is shown at right. This version was created by putting one earthenware pot inside another, filling the space between them with sand and then wetting the sand. Food is stored in the inner pot which can be covered by a wet towel or a lid. As the water evaporates from the sand, it cools the inner pot and its contents. The whole thing is easy to build and to operate and, best of all, it is inexpensive. An added bonus is that the water used for cooling does not need to be potable. That sounds perfect for third world applications and it is most often in this context that the device is discussed.

If you don't already know, a Zeer pot is a type of evaporative refrigerator. It is a device that keeps being rediscovered even though various versions of the device have been used for thousands of years. I am going to call them evaporative refrigerators since they operate by evaporation and are used like a refrigerator. Every new blog entry or YouTube video about them seems to spread misinformation and sometimes outrageous claims. Let’s clear some things up.